Projectors are used today in a multitude of applications. Projectors can be used for presentations or for projecting a film, for example.
Different technologies are used for projecting images or videos. Light sources can be configured behind one or a plurality of LCD displays through which the light passes, for example. Thus, the image shown on the LCD display can be projected onto a screen, for example.
Alternatively, micromirrors can be used for constructing an image, for example. A micromirror-based projector has one or a plurality of micromirrors that are irradiated by a light source, for example, a laser. To project different image contents, these micromirrors are excited to an oscillation. Depending on the amplitude of the oscillation, respectively the position of the mirror, the laser beam is either reflected on or not reflected off of the projection surface.
Such micromirrors are usually resonantly excited to an oscillation. Excitations of the mirror thereby occur in oscillatory rotary motion, for example.
The oscillatory rotary motion is advantageous since light, for example, a laser beam, can be used here for a long-range deflection over small angles. A rotationally oscillating system is thereby used for the excitation.
The decoupling of the vibrational energy and the associated high damping of the oscillating system, which lead to an increased energy demand, are typically disregarded. Also disregarded is the excitation by external oscillations.
For example, if such a system is used in a cell phone as a deflection unit for generating images, and if a speaker is simultaneously active in this cell phone (for example, when video films are played back), then, by transmitting acoustic oscillations (possibly even through air oscillations), the speaker can excite the mirror deflection unit in one of the eigenmodes thereof and thereby disturb the construction of the image.
U.S. Patent Application Publication No. 2013/0250388 A1, for example, describes a resonantly excited mirror.